In the mobile communication system, the Time Division Duplexing (TDD) mode has been widely used, and in the TDD mode, the uplink/downlink transmission uses one band in common, and the uplink transmission and downlink transmission are performed by way of different slots.
When the TDD band is adjacent to the Frequency Division Duplexing (FDD) band, in order to avoid the transceiving interference between the TDD system and the FDD system deployed in the adjacent band, a segment of idle band needs to act as a protection band between the TDD band and the band of the adjacent FDD system.
Especially in the current environment where the 2G, 3G, and Long Term Evolution (LTE) networks coexist, in order to lower the networking costs, during networking, the networking may need be carried out in the manner of Radio Access Network Sharing (RAN Sharing), and the RAN Sharing manner requires that the TDD system and FDD system should be co-site and even co-antenna; since in the TDD mode, the uplink/downlink transmission use one band in common, in such a band utilization mode, in order to avoid the interference between the TDD system and the FDD system deployed in the adjacent band, an enough wide band needs to be reserved from both sides of the TDD band as the protection band.
As shown in FIG. 1, the first band 101 and the second band 102 in FIG. 1 are FDD licensed bands, wherein the first band 101 is an uplink band in the FDD licensed band, and the second band 102 is a downlink band in the FDD licensed band, and the third band 103 is a band for communication by way of time division duplexing in the TDD licensed band. The uplink band and the downlink band are totally overlapped, the fourth band 104 is a protection band between the band for communication in the TDD licensed band and the uplink band in the FDD licensed band, and the fifth band 105 is a protection band between the band for communication in the TDD licensed band and the downlink band in the FDD licensed band.
In the communication system, the band resources are very shortage, and usually the protection band is in the idle state but neither can be used by the TDD system nor can be used by the FDD system, causing the waste of band resources.